Yi Yang教授:实现自由电子与光的最大化相互作用



Title: Towards maximal free-electron-light interaction



主讲人:Yi Yang教授

报告摘要: The interaction between free electrons and photons gives rise to a multitude of fundamental radiative processes in electrodynamics and is foundational for modern electron microscopy and spectroscopy, particle acceleration, and biomedical applications. The dimensionality mismatch between free electrons and photons intrinsically limits their interaction strength. It is thus pertinent to elucidate if there are fundamental bounds to the interaction strength and, if so, how to approach them in nanophotonic environments. We previously derived a single-frequency upper limit to the spontaneous photon emission and energy loss of free electrons, regardless of geometry, which illuminates the effects of material properties and electron velocities [1]. Guided by this upper limit, we identified photonic flatband resonances as a potential candidate for strong free-electron-light interaction [2]. We designed flatband resonances in a silicon-on-insulator photonic crystal slab to control and enhance the associated free-electron radiation by tuning their trajectory and velocity. We observed signatures of flatband enhancement, realized polarization shaping of free-electron radiation, and characterized photonic bands through electron-beam measurements. Very recently, we generalized the upper limit in the quantum regime by deriving the maximal quantum interaction strength between free electrons and photons [3].


[1] Y. Yang et al., Nat. Phys. 14, 894 (2018)

[2] Y. Yang et al., Nature 613, 42 (2023)

[3] Z. Xie et al., arXiv:2404.00377


杨易教授,2011年和2014年在北京大学取得学士和硕士学位,2019年在麻省理工学院(MIT)取得博士学位。2019~2022年在MIT从事博士后研究,并于20225月加入香港大学物理系。杨易教授的研究领域为光物理和纳米光子学,主要方向包括光与物质的相互作用、自由电子和合成规范场。目前,杨易教授以第一作者或通讯作者在NatureScienceNature PhysicsPRL等期刊发表文章40余篇,并获得国家优秀青年基金(港澳)、亚洲青年科学家基金、香港大学百人项目等资助,20235月被MIT评为中国35岁以下最具创新研究员之一。杨易教授还是《Advanced Photonics》青年编委。